The Two Translationally Controlled Tumor Protein Genes, CsTCTP1 and CsTCTP2, Are Negative Modulators in the Cucumis sativus Defense Response to Sphaerotheca fuliginea

Abstract

Pathogen stress often significantly decreases cucumber production. However, knowledge regarding the molecular mechanism and signals of cucumber disease resistance is far from complete. Here, we report two translationally controlled tumor protein genes, CsTCTP1 and CsTCTP2, that are both negative modulators in the Cucumis sativus defense response to Sphaerotheca fuliginea. Subcellular localization analysis showed that CsTCTP1 and CsTCTP2 were both localized in the cytoplasm. Expression analysis indicated that the transcript levels of CsTCTP1 and CsTCTP2 were linked to the degree of cucumber resistance to S. fuliginea. Transient overexpression of either CsTCTP1 or CsTCTP2 in cucumber cotyledons impaired resistance to S. fuliginea, whereas silencing of either CsTCTP1 or CsTCTP2 enhanced cucumber resistance to S. fuliginea. The relationship of several defense-related genes and ABA and target of rapamycin (TOR) signaling pathway-related genes to the overexpressing and silencing of CsTCTP1/CsTCTP2 in non-infested cucumber plants was investigated. The results indicated that CsTCTP1 participates in the defense response to S. fuliginea by regulating the expression of certain defense-associated genes and/or ABA signaling pathway-associated genes, and CsTCTP2 participates through regulating the expression of TOR signaling pathway-associated genes. Our findings will guide enhancing the resistance of cucumber to powdery mildew.

Comparative analysis of powdery mildew resistant and susceptible cultivated cucumber (Cucumis sativus L.) varieties to reveal the metabolic responses to Sphaerotheca fuliginea infection

“…A number of cucumber genes and proteins responsive to S. fuliginea infection have been reported recently [ 14 , 31 ]. Our previous study has mined several candidate genes associated with PM resistence in cucumber by specific length amplified fragment sequencing.…”

“…In the past years, a number of PM-resistance-related genes and metabolites have been identified in various cucumber varieties [ 8 , 11 – 13 ]. Two cucumber translationally controlled proteins, CsTCTP1 and CsTCTP2, were identified as negative regulators in the defense responses to S. fuliginea infection [ 14 ]. CsPTI1 encoding a cytoplasmic kinase involved in defense responses to the fungal pathogen S. fuliginea [ 15 ].…”

Cucumber Mildew Resistance Locus O Interacts with Calmodulin and Regulates Plant Cell Death Associated with Plant Immunity

“…These genes functioned in the defense response to C. cassiicola ; thus, whether the CsMLO1 and CsMLO2 genes affected the transcription levels of CsCaM1 , CsCaM2 , and CsCaM3 was further investigated. In a previous study, an experimental method for the transient agroinfiltration of cucumber cotyledons was established [14,27,28]. Here, a fragment 387 bp in length between the CsMLO1/CsMLO2 and the green fluorescent protein (GFP) fusion genes was detected via PCR analysis in cucumber cotyledons transiently overexpressing CsMLO1/CsMLO2 (Figure 1A).…”

“…TRV-based VIGS technology has been effectively used in cucumber reverse genetics research and can detect the functions of defense-related genes in cucumber plants [14,27,28]. The defense resistance of CsMLO1 silencing was evaluated following C. cassiicola inoculation for 5 days in transgenic cucumbers (Figure 11).…”

Genomic Characterization of WRKY Transcription Factors Related to Andrographolide Biosynthesis in Andrographis paniculata

“…As the demand for andrographolide has grown over the past years, obtaining higher contents of andrographolide by controlling the biosynthesis pathway of andrographolide has attracted researchers' attention. Transcription factors are important regulators that can activate biosynthetic enzyme genes at the transcription level to promote active compound production (Bai et al, 2018 ; Cao et al, 2018 ; Pan et al, 2019 ). In A. paniculata , transcription factors have rarely been studied.…”